Mailing Lists: Apple Mailing Lists

Image of Mac OS face in stamp
 
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: What to use observeValueForKeyPath: context



On Aug 29, 2008, at 10:23, j o a r wrote:
If you use a constant string, you should make sure that the
string *contents* are unique, in order to ensure uniqueness of the
pointer to it. So don't call it @"context", use @"MyFunkyClass KVO
observer context". After all there's no penalty for being verbose in
this case. Of course using a pointer to a global solves this too.


The penalty for using constant strings is that they will end up wasting space in your binary...
Rons suggestion is probably optimal.


Even more optimal than...

static NSString *ABCFooPropertyObservingContext;

is this:

static char ABCFooPropertyObservingContext;

and then still using &ABCFooPropertyObservingContext as the context value. If nothing ends up being packed up tight right after that char, due to data alignment, well then you still haven't lost anything.


Chris Kane Cocoa Frameworks, Apple


_______________________________________________

Cocoa-dev mailing list (email@hidden)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/cocoa-dev/email@hidden

This email sent to email@hidden
References: 
 >What to use observeValueForKeyPath: context (From: Dave Dribin <email@hidden>)
 >Re: What to use observeValueForKeyPath: context (From: "Michael Ash" <email@hidden>)
 >Re: What to use observeValueForKeyPath: context (From: Dave Dribin <email@hidden>)
 >Re: What to use observeValueForKeyPath: context (From: "Michael Ash" <email@hidden>)
 >Re: What to use observeValueForKeyPath: context (From: j o a r <email@hidden>)



Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Contact Apple | Terms of Use | Privacy Policy

Copyright © 2007 Apple Inc. All rights reserved.